Expanding window fountain codes for unequal error protection

A novel approach to provide unequal error protection (UEP) using rateless codes over erasure channels, named Expanding Window Fountain (EWF) codes, is developed and discussed. EWF codes use a windowing technique rather than a weighted (non-uniform) selection of input symbols to achieve UEP property. The windowing approach introduces additional parameters in the UEP rateless code design, making it more general and flexible than the weighted approach. Furthermore, the windowing approach provides better performance of UEP scheme, which is confirmed both theoretically and experimentally

Link-Layer Coding for GNSS Navigation Messages

In this paper, we face the problem of ensuring reliability of Global Navigation Satellite Systems (GNSSs) in harsh channel conditions, where obstacles and scatter cause long outage events that cannot be counteracted with channel coding only. Our novel approach, stemming from information-theoretic considerations, is based on link-layer coding (LLC). LLC allows us to significantly improve the efficiency in terms of time-to-first-fix with respect to current operational GNSSs, which adopt carousel transmission. First, we investigate the maximum theoretical LLC gain under different Land Mobile Satellite channel conditions. Then, some practical LLC coding schemes, namely, fountain codes and a novel low-density parity-check plus low-rate repetition coding, are proposed and tested in realistic single-satellite and multi-satellite Land Mobile Satellite scenarios, considering the Galileo I/NAV message as study case. Simulation results show that our designed schemes largely improve on carousel transmission and achieve near-optimal performance with limited increase in complexity. Also, back-compatibility of LLC is assessed with respect to present-time GNSS specifications. © 2018 Institute of Navigation

Evaluation of cross-layer reliability mechanisms for satellite digital multimedia broadcast

This paper presents a study of some reliability mechanisms which may be put at work in the context of Satellite Digital Multimedia Broadcasting (SDMB) to mobile devices such as handheld phones. These mechanisms include error correcting codes, interleaving at the physical layer, erasure codes at intermediate layers and error concealment on the video decoder. The evaluation is made on a realistic satellite channel and takes into account practical constraints such as the maximum zapping time and the user mobility at several speeds. The evaluation is done by simulating different scenarii with complete protocol stacks. The simulations indicate that, under the assumptions taken here, the scenario using highly compressed video protected by erasure codes at intermediate layers seems to be the best solution on this kind of channel

COST EFFICIENT PROVISIONING OF MASS MOBILE MULTIMEDIA SERVICES IN HYBRID CELLULAR AND BROADCASTING SYSTEMS

Uno de los retos a los que se enfrenta la industria de las comunicaciones móviles e inalámbricas es proporcionar servicios multimedia masivos a bajo coste, haciéndolos asequibles para los usuarios y rentables a los operadores. El servicio más representativo es el de TV móvil, el cual se espera que sea una aplicación clave en las futuras redes móviles. Actualmente las redes celulares no pueden soportar un consumo a gran escala de este tipo de servicios, y las nuevas redes de radiodifusión móvil son muy costosas de desplegar debido a la gran inversión en infraestructura de red necesaria para proporcionar niveles aceptables de cobertura. Esta tesis doctoral aborda el problema de la provisión eficiente de servicios multimedia masivos a dispositivos móviles y portables utilizando la infraestructura de radiodifusión y celular existente. La tesis contempla las tecnologías comerciales de última generación para la radiodifusión móvil (DVB-H) y para las redes celulares (redes 3G+ con HSDPA y MBMS), aunque se centra principalmente en DVB-H. El principal paradigma propuesto para proporcionar servicios multimedia masivos a bajo coste es evitar el despliegue de una red DVB-H con alta capacidad y cobertura desde el inicio. En su lugar se propone realizar un despliegue progresivo de la infraestructura DVB-H siguiendo la demanda de los usuarios. Bajo este contexto, la red celular es fundamental para evitar sobre-dimensionar la red DVB-H en capacidad y también en áreas con una baja densidad de usuarios hasta que el despliegue de un transmisor o un repetidor DVB-H sea necesario. Como principal solución tecnológica la tesis propone realizar una codificación multi-burst en DVB-H utilizando códigos Raptor. El objetivo es explotar la diversidad temporal del canal móvil para aumentar la robustez de la señal y, por tanto, el nivel de cobertura, a costa de incrementar la latencia de la red.Gómez Barquero, D. (2009). COST EFFICIENT PROVISIONING OF MASS MOBILE MULTIMEDIA SERVICES IN HYBRID CELLULAR AND BROADCASTING SYSTEMS [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/6881Palanci

Performance evaluation of AL-FEC LDPC codes for push content applications in wireless unidirectional environments

The final publication is available at Springer via http://dx.doi.org/10.1007/s11042-011-0841-yFEC (Forward Error Correction) mechanisms improve IP content transmission reliability through the recovery of packets lost in transmission. Opposite to ARQ (Automatic Repeat Request), FEC mechanisms are especially suited to unidirectional environments or to multicast environments where multiple receivers perceived different channel losses, thus making difficult the implementation of mechanisms based on feedback information. Among the different types of FEC codes, this paper presents a thorough performance evaluation of LDPC (Low Density Parity Check) codes, based on an implementation developed by the authors, according to the specifications defined by RFC 5170 for the usage of LDPC codes by push content applications based on the FLUTE protocol. LDPC codes provide a good trade-off between performance and complexity, hence, they are appropriate for mobile applications. Contributions of this paper include tests conducted with commercial mobile phones connected to the push content download server over a Wi-Fi network. The evaluation highlights the advantages of using packet level FEC encoding in file transmission over unidirectional networks and provides with a comparison between two kinds of LDPC structures: Staircase and Triangle. This is accomplished by calculating the inefficiency ratio of these LDPC structures in different environments. Results show that the implemented LDPC codes can provide inefficiency ratios close to one when the different coding parameters (as the code rate or the number of blocks) are configured to an optimal value that depends on the packet loss rate. © 2011 Springer Science+Business Media, LLC.This work was supported in part by the Ministry of Industry, Tourism and Trade of the Government of Spain, under project "Redes Hibridas para la Provision de Servicios Turisticos" (TSI-020302-2010-165).De Fez Lava, I.; Fraile Gil, F.; Belda Ortega, R.; Guerri Cebollada, JC. (2012). Performance evaluation of AL-FEC LDPC codes for push content applications in wireless unidirectional environments. Multimedia Tools and Applications. 60(3):669-688. https://doi.org/10.1007/s11042-011-0841-yS6696886033GPP TS 22.146 (2006) Multimedia broadcast/multicast service; stage 1 (release 6), V6.7.03GPP TS 25.346 (2007) Introduction of the Multimedia Broadcast Multicast Service (MBMS) in the Radio Access Network (RAN); Stage 2 (Release8), V8.0.0Bai H, Atiquzzaman M (2003) Error modeling schemes for fading channels in wireless communications: a survey. IEEE Comm Surv Tutorials 5(2)Cunche M, Roca V (2008) Optimizing the error recovery capabilities of LDPC-staircase codes featuring a Gaussian elimination decoding scheme. Proc. of the 10th IEEE International Workshop on Signal Processing for Space Communications (SPSC), Rhodes Island, GreeceCunche M, Roca V (2008) Improving the decoding of LDPC codes for the packet erasure channel with a hybrid Zyablov iterative decoding/Gaussian elimination scheme. INRIA Research Report RR-6473Cunche M, Savin V, Roca V (2010) Analysis of quasi-cyclic LDPC codes under ML decoding over the erasure channel. IEEE International Symposium on Information Theory and its Applications (ISITA), Taichung, TaiwanFaria G, Henriksson J, Stare E, Talmola P (2006) DVB-H: digital broadcast services to handheld devices. Proc IEEE 94(1):194–209Fraile F, de Fez I, Guerri JC (2011) Evaluation of a background push download service for personal multimedia devices. IEEE International Conference on Consumer Electronics, Las Vegas, USAGallager R G (1962), Low density parity check codes. IEEE Trans Inform Theor 8(1)Gil A, Fraile F, Ramos M, de Fez I, Guerri JC (2010) Personalized multimedia touristic services for mobile hybrid broadband/broadcast. IEEE Trans Consum Electron 56(1):129–211Handley M, Jacobson V (1998) SDP: session description protocol. IEFT RFC 2327IEEE (2007) Std. 802.11, wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) specificationsIEEE (2009) Std. 802.16, air interface for broadband wireless systemsLacan J, Roca V, Peltotalo J, Peltotalo S (2009) Reed-Solomon Forward Error Correction (FEC) schemes. IETF RFC 5510Luby M (2002) LT codes. Proc. IEEE Symposium on Foundations of Computer Science (FOCS), Vancouver, CanadaLuby M, Shokrollahi A, Watson M and Stockhammer T (2007) Raptor forward error correction scheme for object delivery. IETF RFC 5053Luby M, Watson M, Vicisano L (2009) Layered Coding Transport (LCT) building block. IEFT RFC 5651Luby M, Watson M, Vicisano L (2010) Asynchronous Layered Coding (ALC) protocol instantiation. IEFT RFC 5775MacKay D, Neal R (1995) Good codes based on very sparse matrices. In 5th IAM Conference: Cryptography and Coding, LNCS No. 1025Paila T, Luby M, Lehtonen R, Roca V, Walsh R (2004) FLUTE—file delivery over unidirectional transport. IETF RFC 3926Park S, Miller K (1990) Random number generators: good ones are hard to find. Commun ACM 33(1):87–88INRIA Planète Research Team (2006) LDPC large block FEC codec distribution, http://planete-bcast.inrialpes.fr/article.php3?id_article=16Roca V, Neumann C (2004) Design, evaluation and comparison of four large block FEC codecs, LDPC, LDGM, LDGM staircase and LDGM triangle, plus a Reed-Solomon small block FEC codec. INRIA Research Report RR-5225Roca V, Neumann C, Furodet D (2008) Low Density Parity Check (LDPC) Staircase and Triangle Forward Error Correction (FEC) schemes. IETF RFC 5170Shokrollahi A (2006) Raptor codes. IEEE Transactions on Information Theory no. 6Watson M (2009) Basic Forward Error Correction (FEC) schemes. IETF RFC 5445Watson M, Luby M, Vicisano L (2007) Forward Error Correction (FEC) building block. IETF RFC 5052White Paper (2009) Integrated Mobile Broadcast (IMB): the power of predictive broadcasting for 3G multimedia application

Performance Analysis of NOMA Multicast Systems Based on Rateless Codes with Delay Constraints

To achieve an efficient and reliable data transmission in time-varying conditions, a novel non-orthogonal multiple access (NOMA) transmission scheme based on rateless codes (NOMA-RC) is proposed in the multicast system in this paper. Using rateless codes at the packet level, the system can generate enough encoded data packets according to users’ requirements to cope with adverse environments. The performance of the NOMA-RC multicast system with delay constraints is analyzed over Rayleigh fading channels. The closed-form expressions for the frame error ratio and the average transmission time are derived for two cases which are a broadcast communication scenario (Scenario 1) and a relay communication scenario (Scenario 2). Under the condition that the quality of service for the edge user is satisfied, an optimization model of power allocation is established to maximize the sum rate. Simulation results show that Scenario 2 can provide better block error ratio performance and exhibit less transmission time than Scenario 1. When compared with orthogonal multiple access (OMA) with rateless codes system, the proposed system can save on the transmission time and improve the system throughput